Suspicious Diamond Sleet Anomalous Microsoft Internet Explorer User Agent (via proxy)

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1071.001Web Protocols
Exfiltration
Impact

What it detects

This rule detects outbound requests carrying the literal user agent string Microsoft Internet Explorer, which does not match any genuine Internet Explorer user agent. Diamond Sleet LambLoad used this hardcoded user agent when fetching PNG-disguised second-stage payloads.

Reporting behind it

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Suspicious Diamond Sleet Anomalous Microsoft Internet Explorer User Agent (via proxy)

Pivot detection · T1071.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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